    (when-not content
      (throw (ex-info "Block must have a content reader"
                      {:id id, :size size, :stored-at stored-at})))
-   (Block. id size stored-at content nil 0)))
+   (Block. id size stored-at content nil)))
 
 
 (defn load-block

          (.size right)
          (.stored-at right)
          (.content right)
          (not-empty (merge (._meta left) (._meta right)))
          0))


(defn wrap-content

          (.size block)
          (.stored-at block)
          (f (.content block))
          (._meta block)))
